Propagation of metal vapor vacuum arc ions into electron cyclotron resonance ion sources

A metal vapor vacuum arc (Mevva) ion source was finally installed and operated inside the electron cyclotron resonance (ECR) ion source Alice; Mevva cathode was made of Al, while ECR buffer gas was nitrogen, and among residuals, argon. Installation, hardware control, and improvements of diagnostic are discussed. Magnetic analysis of the ECR emitted current shows the presence of an Al3+ peak of about 5–10 μA following Mevva pulse end after 15 μs, against a steady state current of 10 nA. Peak width is about 5 μs, which is the limit of our current amplifier. Peak remains when ECR is turned off. Application of a bias potential of ±46 V to the Mevva anode shows fairly small effects on time of flight, which may indicate a large kinetic energy of Mevva ions (280 eV) at the end of Mevva shot. Bias voltage and ECR operation proved compatible only at low power, in present installation; then, some or most of Mevva ions are not trapped inside the ECR.